Thin films of ABO3 with excess B-site modifiers and method of fabricating integrated circuits with same

Abstract

A method for fabricating an integrated circuit capacitor having a dielectric layer comprising BST with excess B-site material, such as titanium, added. A polyoxyalkylated metal liquid precursor solution is prepared comprising a stock solution of BST of greater then 99.999% purity blended with excess B-site material such as titanium such that the titanium is in the range of 0-100 mol %. A xylene exchange is then performed to adjust the viscosity of the solution for spin-on application to a substrate. The precursor is spun on a first electrode, dried at 400 DEG C. for 2 minutes, then annealed at 650 DEG C. to 800 DEG C. for about an hour to form a layer of BST with excess titanium. A second electrode is deposited, patterned, and annealed at between 650 DEG C. to 800 DEG C. for about 30 minutes. The resultant capacitor exhibits an enlarged dielectric constant with only a small increase in leakage current.

We claim: 
     
       1. A non-stoichiometric metal oxide precursor solution for fabricating integrated circuit thin films, said precursor solution comprising: a stoichiometric portion including total A-site and total B-site metals in a 1:1 ratio capable of satisfying a formula; and   excess B-site material added to said stoichiometric portion including B-site material in an amount ranging from 0.01 mol % to 100 mol % of the amount of total amount of B-site material required to satisfy said formula.   
     
     
       2. The precursor of claim 1 wherein said stoichiometric portion comprises barium, strontium, and titanium in amounts corresponding to a formula (Ba x  Sr 1-x  TiO 3 ), wherein x is a number ranging from zero to one. 
     
     
       3. The precursor of claim 2 wherein said excess B-site material comprises titanium in an amount greater than 0.1 mol % and less than 20 mol %. 
     
     
       4. The precursor of claim 1 wherein said excess B-site material comprises titanium in an amount ranging from 1 mol % to 3 mol %.